You need 10 weeks for liverpool. 6 week other, 4 week vet. Vet should be with at least two different practices, try to get small animal and large animal work e.g. farm or equine vet. For the other, try kennels, stables, dairy farms ( essential), lambing or calving, pig farm, turkey farms, goat farms, city farms and maybe a day in an abbatoir. After that its anything to make your application stand out.. I think its 5As at least at GCSE, with As in science.